Great horned owls are the most familiar owl for most people. They are the owl that’s pictured in storybooks and the one whose call people are most familiar with. But they don’t actually have horns. And those horn-like projections on each side of their heads aren't ears either. The “horns” are really just tufts of feathers.
The tufts are called plumicorns, and great horned owls aren’t the only owls that have them. Other owls that have plumicorns include long-eared owls, short-eared owls and eastern screech owls. Of all these owls, though, great horned owls have the most prominent plumicorns, and it’s obviously how they got their name.